GLASS-CERAMIC AND SUBSTRATE THEREOF

Abstract

A glass ceramic contains the following components by wt %: 60 to 80% of SiO2; 4 to 20% of Al2O3; 0 to 15% of Li2O; more than 0 but less than or equal to 12% of Na2O; 0 to 5% of K2O; more than 0 but less than or equal to 5% of ZrO2; 0 to 5% of P2O5; and 0 to 10% of TiO2. A crystalline phase contains at least one of R2SiO3, R2Si2O5, R2TiO3, R4Ti5O12, R3PO3, RAlSi2O6, RAlSiO4O10, R2Al2Si2O5, R4Al4Si5O18, quartz and quartz solid solution. With a liquidus temperature below 1,450° C., a thermal conductivity above 2 w/m·k, and a Vickers hardness above 600 kgf/mm2, the glass ceramic is applicable to portable electronic devices and optical devices.

Description

TECHNICAL FIELD

The present invention relates to a glass ceramic and a substrate using the glass ceramic as a matrix. In particular, the present invention relates to a glass ceramic and substrate applicable to protective components such as portable electronic devices or optical devices and having high thermal conductivity and high strength.

BACKGROUND

Back covers are required for portable electronic devices such as smart phones, tablet PCs and other optical devices to protect internal electronic devices. Protective materials for the back covers, especially for electronic devices requiring wireless signals should have relatively high thermal conductivity, individualized colors and relatively high strength, can be used in harsh environments, and have good processing performance. In the past, metals were usually used as the protective materials for the back covers, but metal back covers would seriously affect reception of signals and could only be designed as sectional type. With development of 5G signals, the metal back covers are no longer feasible.

Ceramic materials have good texture and relatively high thermal conductivity without impact on signals, but have poor processability and higher cost compared with glass. At present, simple glass has low thermal conductivity and insufficient strength, which restrains its use as a back cover material for electronic devices.

Glass ceramic, also known as microcrystalline glass, separates out crystals in glass by heat treatment. Through internal dispersed crystals, glass ceramic can have physical properties unavailable in glass. Examples include mechanical strength such as Young's modulus and fracture toughness, etching properties for acidic or alkaline chemicals, thermal properties such as thermal expansion coefficient, increase and disappearance of glass transition temperature. Glass ceramic has higher mechanical properties and can improve thermal conductivity of glass due to formation of microcrystals in the glass. However, the glass ceramic in the past is not applicable to the protective materials due to poor thermal conductivity and strength. In addition, the conventional glass ceramic is rather unfit to be used as the protective material due to low productivity as a result of high viscosity or high devitrification resistance of raw glass.

Japanese Patent Document (made public under special permission) No. 2014-114200 discloses a glass ceramic substrate for information recording media. After chemical tempering, the glass ceramic substrate is unable to obtain a sufficient compressive stress and cannot form a deeper stress layer.

SUMMARY

A technical problem to be solved by the present invention is to provide a glass ceramic and substrate with relatively high thermal conductivity and strength.

The technical solution of the invention for solving the technical problem is as follows: a glass ceramic, contains the following components by wt %: 60 to 80% of SiO₂; 4 to 20% of Al₂O₃; 0 to 15% of Li₂O; more than 0 but less than or equal to 12% of Na₂O; 0 to 5% of K₂O; more than 0 but less than or equal to 5% of ZrO₂; 0 to 5% of P₂O₅; and 0 to 10% of TiO₂, wherein a crystalline phase contains at least one selected from R₂SiO₃, R₂Si₂O₅, R₂TiO₃, R₄Ti₅O₁₂, R₃PO₃, RAlSi₂O₆, RAlSiO₄O₁₀, R₂Al₂Si₂O₅, R₄Al₄Si₅O₁₈, quartz and quartz solid solution, and R is at least one selected from Li, Na and K.

Further, the glass ceramic also contains 0 to 5% of B₂O₃; and/or 0 to 2% of MgO; and/or 0 to 2% of ZnO; and/or 0 to 5% of CaO; and/or 0 to 5% of BaO; and/or 0 to 3% of FeO; and/or 0 to 2% of SnO₂; and/or 0 to 5% of SrO; and/or 0 to 10% of La₂O₃; and/or 0 to 10% of Y₂O₃; and/or 0 to 10% of Nb₂O₅; and/or 0 to 10% of Ta₂O₅; and/or 0 to 5% of WO₃.

A glass ceramic, is composed of the following components by wt %:60 to 80% of SiO₂; 4 to 20% of Al₂O₃; 0 to 15% of Li₂O; more than 0 but less than or equal to 12% of Na₂O; more than 0 but less than or equal to 5% of ZrO₂; 0 to 5% of P₂O₅; 0 to 10% of TiO₂; 0 to 5% of B₂O₃; 0 to 5% of K₂O; 0 to 2% of MgO; 0 to 2% of ZnO; 0 to 5% of CaO; 0 to 5% of BaO; 0 to 3% of FeO; 0 to 2% of SnO₂; 0 to 5% of SrO; 0 to 10% of La₂O₃; 0 to 10% of Y₂O₃; 0 to 10% of Nb₂O₅; 0 to 10% of Ta₂O₅; 0 to 5% of WO₃; and 0 to 5% of a clarificant, wherein a crystalline phase contains at least one selected from R₂SiO₃, R₂Si₂O₅, R₂TiO₃, R₄Ti₅O₁₂, R₃PO₃, RAlSi₂O₆, RAlSiO₄O₁₀, R₂Al₂Si₂O₈, R₄Al₄Si₅O₁₈, quartz and quartz solid solution, and R is at least one selected from Li, Na and K.

Further, SiO₂ accounts for 65 to 78%; and/or Al₂O₃ accounts for 5 to 18%; and/or 0 to 12% of Li₂O; and/or Na₂O accounts for 0.5 to 10%; and/or ZrO₂ accounts for 0.4 to 3%; and/or P₂O₅ accounts for 0.4 to 3%; and/or B₂O₃ accounts for 0 to 4%; and/or K₂O accounts for 0.5 to 4%; and/or MgO accounts for more than 0 but less than or equal to 2%; and/or ZnO accounts for more than 0 but less than or equal to 2%; and/or CaO accounts for 0 to 4%; and/or BaO accounts for 0 to 4%; and/or FeO accounts for 0 to 1%; and/or SnO₂ accounts for 0.01 to 1%; and/or SrO accounts for 0 to 3%; and/or La₂O₃ accounts for 0 to 9%; and/or Y₂O₃ accounts for 0 to 9%; and/or Nb₂O₅ accounts for 0 to 8%; and/or Ta₂O₅ accounts for 0 to 8%; and/or WO₃ accounts for 0 to 2%; and/or the clarificant contains As₂O₃, Sb₂O₃ and CeO₂ and at least one selected from the group consisting of F, Cl, NOx and SOx with a content of 0 to 5%.

Further, SiO₂/Li₂O ratio is 4 to 10; and/or ZrO₂/Li₂O ratio is 0 to 0.5; and/or Al₂O₃/(Na₂O+Li₂O) ratio is 0.5 to 2; and/or Li₂O/Na₂O ratio is 0.8 to 8.

Further, SiO₂ accounts for 68 to 75%; and/or Al₂O₃ accounts for 6 to 15%; and/or Li₂O accounts for 6 to 10%; and/or Na₂O accounts for 2 to 8%; and/or ZrO₂ accounts for 0.8 to 2%; and/or P₂O₅ accounts for 0.8 to 2%; and/or TiO₂ accounts for 1 to 4%; and/or B₂O₃ accounts for more than 0% but less than 2%; and/or K₂O accounts for 0.8 to 3%; and/or CaO accounts for 0 to 3%; and/or BaO accounts for 0 to 3%; and/or SnO₂ accounts for 0.05 to 0.4%; and/or SrO accounts for 0 to 1%; and/or La₂O₃ accounts for more than 0 but less than or equal to 8%; and/or Y₂O₃ accounts for more than 0 but less than or equal to 8%; and/or Nb₂O₅ accounts for 0 to 5%; and/or Ta₂O₅ accounts for 0 to 5%; and/or WO₃ accounts for 0 to 1%; and/or the clarificant accounts for 0 to 2%.

Further, SiO₂/Li₂O ratio is 4.5 to 9.5; and/or ZrO₂/Li₂O ratio is more than 0 but less than 0.35; and/or Al₂O₃/(Na₂O+Li₂O) ratio is 0.7 to 1.8; and/or Li₂O/Na₂O ratio is 1.5 to 7.5.

Further, Na₂O accounts for 4 to 8%, preferably more than 5% but less than or equal to 8%; and/or Al₂O₃ accounts for 7 to 15%; and/or ZrO₂ accounts for 1 to 2%; and/or P₂O₅ accounts for 1 to 2%; and/or K₂O accounts for 1 to 3%; and/or CaO accounts for 0 to 1%; and/or BaO accounts for 0 to 1%; and/or SnO₂ accounts for 0.05 to 0.2%; and/or the clarificant accounts for 0 to 1%; and/or SiO₂/Li₂O ratio is 5 to 9; and/or ZrO₂/Li₂O ratio is more than 0 but less than or equal to 0.30; and/or Al₂O₃/(Na₂O+Li₂O) ratio is 1 to 1.5; and/or Li₂O/Na₂O ratio is 2 to 7, preferably Li₂O/Na₂O ratio is 2 to 6.

Further, TiO₂ accounts for 0.5 to 5%, preferably TiO₂ accounts for 1.5 to 4%; and/or ZrO₂+P₂O₅+TiO₂ account for 0.5 to 10%, preferably ZrO₂+P₂O₅+TiO₂ account for 1 to 8%, and more preferably ZrO₂+P₂O₅+TiO₂ account for 2 to 6%.

Further, TiO₂ accounts for 2 to 9.5%, preferably TiO₂ accounts for 5 to 8.5%; and/or ZrO₂+P₂O₅+TiO₂ account for 1 to 16%, preferably ZrO₂+P₂O₅+TiO₂ account for 2 to 12%.

Further, the glass ceramic also contains NiO and/or Ni₂O₃ with total amount thereof not more than 6%, preferably not more than 4%, more preferably not more than 3%, and a lower limit of the total amount thereof more than 0.1%; or the glass ceramic contains Pr₂O₅ with content not more than 8%, preferably not more than 6%, more preferably not more than 5%, and a lower limit of the content thereof more than 0.4%; or the glass ceramic contains CoO and/or Co₂O₃ with total amount thereof not more than 2%, preferably not more than 1.8%, and a lower limit of the total amount thereof more than 0.05%; or the glass ceramic contains Cu₂O and/or CeO₂ with total amount thereof not more than 4%, preferably not more than 3%, and a lower limit of the total amount thereof more than 0.5%; or the glass ceramic contains Fe₂O₃ with content not more than 8%, preferably not more than 5%, and more preferably not more than 3%; or the glass ceramic contains Fe₂O₃ and CoO with CoO not more than 0.3%; or the glass ceramic contains Fe₂O₃ and CO₂O₃ with CO₂O₃ not more than 0.3%; or the glass ceramic contains Fe₂O₃, CoO and NiO; or the glass ceramic contains Fe₂O₃, CO₂O₃ and NiO; or the glass ceramic contains Fe₂O₃, CoO and CO₂O₃ with a lower limit of the total amount of CoO and CO₂O₃ more than 0.2%; or the glass ceramic contains Fe₂O₃, CoO, NiO and Co₂O₃; or the glass ceramic contains MnO₂ with content not more than 4%, preferably not more than 3%, and a lower limit of the content thereof more than 0.1%; or the glass ceramic contains Er₂O₃ with content not more than 8%, preferably not more than 6%, and a lower limit of the content thereof more than 0.4%; or the glass ceramic contains Nd₂O₃ with content not more than 8%, preferably not more than 6%, and a lower limit of the content thereof more than 0.4%; or the glass ceramic contains Er₂O₃, Nd₂O₃ and MnO₂ with Er₂O₃ content within 6%, Nd₂O₃ content within 4%, and MnO₂ content within 2%, and a lower limit of the total amount thereof more than 0.9%; or the glass ceramic contains Cr₂O₃ with content not more than 4%, preferably not more than 3%, more preferably not more than 2%, and a lower limit of the content thereof more than 0.2%; or the glass ceramic contains V₂O₅ with content not more than 4%, preferably not more than 3%, more preferably not more than 2%, and a lower limit of the content thereof more than 0.2%.

Further, the Li₂Si₂O₅ crystalline phase accounts for 20 to 40% of the glass ceramic by wt %, preferably 20 to 35%, more preferably 20 to 30%, and still more preferably 20 to 25%.

Further, the quartz and the quartz solid solution crystalline phase account for 15 to 30% of the glass ceramic by wt %, preferably 20 to 30%, more preferably 25 to 30%.

Further, the Li₂Si₂O₅ crystalline phase, the quartz and the quartz solid solution are main crystalline phases, and the total content thereof accounts for less than 50% of the glass ceramic by wt %, preferably 48% or less, and more preferably 46% or less.

Further, LiAlSi₄O₁₀ crystalline phase accounts for not more than 15% of the glass ceramic by wt %.

Further, an upper limit of liquidus temperature is 1450° C., preferably 1400° C., more preferably 1380° C., and most preferably 1320° C.

Further, thermal conductivity of the glass is above 2 W/m·k at room temperature (25° C.).

A glass ceramic substrate made of the glass ceramic by chemical tempering.

Further, Vickers hardness (Hv) is above 600 kgf/mm², preferably above 650 kgf/mm², and more preferably above 700 kgf/mm².

Further, the glass ceramic substrate does not break when a 32 g steel ball fall to the substrate from a height of 500 mm, and the height is preferably above 650 mm, and more preferably above 800 mm.

Further, three-point bending strength is above 450 Mpa, preferably above 600 Mpa, and more preferably above 800 Mpa.

Further, a compressive stress layer is formed by ion exchange treatment, and compressive stress value of the compressive stress layer is above 300 Mpa, preferably above 400 Mpa, and more preferably above 500 Mpa.

Further, thickness of the compressive stress layer is above 1 μm, preferably above 5 μm, and more preferably above 8 μm.

A portable electronic device containing the glass ceramic.

The portable electronic device, containing the glass ceramic substrate.

The present invention has the following beneficial effects: the thermal conductivity of the glass ceramic of the invention is above 2 w/m·k at room temperature, and the tempered Vickers hardness (Hv) is above 600 kgf/mm². The glass ceramic or substrate of the invention is applicable to protective components of portable electronic devices, optical devices and the like, especially suitable for being as back cover due to high thermal conductivity and strength, good transparency or individualized colors. The glass ceramic of the invention can also be used as a heat conducting material due to high thermal conductivity, and can also be used for other decorative purposes such as for outer frame members of portable electronic devices having unique appearance made of glass materials.

DETAILED DESCRIPTION

The glass ceramic of the invention is a material having both crystalline phase and glass phase and different from amorphous solid. The crystalline phase of the glass ceramic can be identified by the peak angle in the X-ray diffraction pattern from X-ray diffraction analysis and TEMEDX. In the glass ceramic of the invention, a crystalline phase contains at least one of R₂SiO₃, R₂Si₂O₅, R₂TiO₃, R₄Ti₅O₁₂, R₃PO₃, RAlSi₂O₆, RAlSiO₄O₁₀, R₂Al₂Si₂O₅, R₄Al₄Si₅O₁₈, quartz and quartz solid solution, and R is at least one selected from Li, Na and K.

Among them, the Li₂Si₂O₅ crystalline phase is a lithium disilicate crystalline phase which is an orthorhombic crystal based on [Si₂O₅] tetrahedral array, and the crystal is flat or platy. In the interior of the glass ceramic, the lithium disilicate crystalline phase is an irregular and non-oriented interlocking microstructure, which forces crack to bend path when passing through the crystal, thus preventing the crack from propagation and improving strength and toughness of the glass ceramic. Compared with the glass phase, the lithium disilicate crystalline phase has higher thermal conductivity, thus improving the thermal conductivity of the glass ceramic. In the glass ceramic of the invention, the Li₂Si₂O₅ crystalline phase accounts for 20 to 40% of the glass ceramic by wt %, preferably 20 to 35%, more preferably 20 to 30%, and still more preferably 20 to 25%.

The quartz and the quartz solid solution crystalline phase belong to trigonal or hexagonal crystal systems, and exist in the form of spheres in the glass ceramic, which can further prevent propagation of microcracks and improve bending strength and toughness of the glass ceramic. Compared with the glass phase, the quartz and the quartz solid solution crystalline phase have higher thermal conductivity, thus improving the thermal conductivity of the glass ceramic. The quartz and the quartz solid solution crystalline phase account for 15 to 30% of the glass ceramic by wt %, preferably 20 to 30%, and more preferably 25 to 30%.

By controlling crystallization process and component content, the glass ceramic uses the Li₂Si₂O₅ crystalline phase, the quartz and the quartz solid solution as main crystalline phases, and total content thereof accounts for less than 50% of the glass ceramic by wt %. Research shows that if the content of the main crystalline phases exceeds 50%, the crystalline phase content is relatively high for glass, resulting in poor tempering effect of the glass ceramic, which is unable to increase strength of the glass, but conversely reduces strength of the glass. The total content of the Li₂Si₂O₅ crystalline phase, the quartz and the quartz solid solution is preferably kept below 48%, more preferably below 46%.

Petalite LiAlSi₄O₁₀ is a monoclinic crystal, a three-dimensional frame structure with a laminated structure made of folded Si₂O₆ layers due to connection by Li and Al tetrahedrons, has a low expansion coefficient, can be used to improve thermal shock resistance of the glass ceramic, acts as an auxiliary crystalline phase of the glass ceramic, and accounts for not more than 15% of the glass ceramic by wt %.

The inventors of the invention have, through repeated tests and studies, obtained the glass ceramic or the glass ceramic substrate of the invention at a low cost by prescribing the content and content ratio of specific components constituting the glass ceramic to specific values and separating out specific crystalline phases. The composition of each components of the glass ceramic of the invention is described below. In the Description, unless otherwise specified, the content of each component is represented by wt % relative to the total amount of glass substances converted into the composition of oxides. Here, “converted into the composition of oxides” refers to that oxides, composite salts and metal fluorides, used as raw materials for the components of the glass ceramic of the present invention, are fully decomposed and converted into the oxide at fusion, and the total amount of the substances of the oxide is 100%. Besides, when the glass is only called in the Description, bare glass before crystallization is included sometimes.

SiO₂ is a necessary component for the formation of a reticular glass structure of the glass ceramic of the present invention and the component of a crystalline phase through thermal treatment of the bare glass. If the amount thereof is lower than 60%, chemical durability and devitrification resistance of the obtained glass are poor. Hence, the lower limit of SiO₂ content is preferably 60%, more preferably 65%, and further preferably 68%. On the other hand, the excessive viscosity rise and the meltability decrease can be constrained by making the SiO₂ content below 80%. Hence, the upper limit of SiO₂ content is preferably 80%, more preferably 78%, and further preferably 75%.

Al₂O₃ and SiO₂ are both the components for the formation of the reticular glass structure, are important components conducive to stabilizing the bare glass and improving chemical durability, and are also capable of improving the thermal conductivity of the glass. But, the effect is poor if the content thereof is lower than 4%. Hence, the lower limit of Al₂O₃ content is 4%, preferably 5%, more preferably 6%, and further preferably 7%. On the other hand, if the Al₂O₃ content is more than 20%, the meltability and the devitrification resistance reduce. Hence, the upper limit of Al₂O₃ content is 20%, preferably 18%, and more preferably 15%.

Li₂O is an optional component to improve the low-temperature meltability and formability of the glass, and can become the necessary component for constituting the required crystalline phase through the thermal treatment of the bare glass. If the content thereof is lower than 6%, the effect is poor. On the other hand, excessive Li₂O can easily lead to decrease of chemical durability or increase in average linear expansion coefficient. Hence, the upper limit of Li₂O content is preferably 15%, more preferably 12%, and further preferably 10%. If the glass ceramic contains Li₂O, it is very effective to form a deep compressive stress layer when chemical tempering is conducted by ion exchange.

Na₂O is an optional component to improve low-temperature meltability and formability, but excessive Na₂O can easily lead to decrease of the chemical durability or increase in the average linear expansion coefficient. Hence, the upper limit of Na₂O content is preferably 12%, more preferably 10%, and most preferably 8%. If the glass ceramic contains Na₂O, it is very effective to form the compressive stress layer by the exchange of Na⁺ and K⁺ ions in the glass ceramic when chemical tempering is conducted by ion exchange. Hence, the lower limit of Na₂O content is more than 0, preferably 0.5%, further preferably 2%, more preferably 4%, and most preferably more than 5% when chemical tempering is conducted by ion exchange.

P₂O₅ can be subject to phase splitting to form a crystal nucleus in the glass, and is an optional component which is conducive to improving the low-temperature meltability of the glass. The lower limit of P₂O₅ content is preferably more than 0, more preferably 0.4%, further preferably 0.8%, and most preferably 1%. But excessive P₂O₅ can easily lead to decrease of the devitrification resistance and phase splitting of the glass. Hence, the upper limit of P₂O₅ content is preferably 5%, more preferably 3%, and most preferably 2%.

ZrO₂ plays a role in separating from a crystal to form the crystal nucleus, and is an optional component to improve the chemical durability of the glass. The lower limit of ZrO₂ content is preferably more than 0, more preferably 0.4%, further preferably 0.8%, and most preferably 1%. But excessive ZrO₂ can easily lead to decrease of the devitrification resistance of the glass. Hence, the upper limit of ZrO₂ content is preferably 5%, more preferably 3%, and most preferably 2%.

TiO₂ is an optional component which is conducive to lowering a melting temperature of the glass ceramic and improving the chemical durability.

In some embodiments, the lower limit of TiO₂ content is preferably more than 0, more preferably 0.5%, further preferably 1%, and most preferably 1.5%. On the other hand, the melting temperature of the glass ceramic can be lowered by making the TiO₂ content below 6%. Hence, the upper limit of TiO₂ content is preferably 6%, more preferably 5%, and most preferably 4%.

In such a condition, the total content of ZrO₂, P₂O₅ and TiO₂ can be controlled to separate out homogeneous crystals, namely, ZrO₂+P₂O₅+TiO₂ accounts for 0.5 to 10%. In order to obtain the effect easier, the lower limit of ZrO₂+P₂O₅+TiO₂ is preferably 0.5%, more preferably 1%, further preferably 2%; and the upper limit of ZrO₂+P₂O₅+TiO₂ is preferably 10%, more preferably 8%, and further preferably 6%.

In some embodiments, the glass is devitrified easily due to high total content of Li₂O and Na₂O in the glass, and free oxygen of the glass can be absorbed to form a network forming body after TiO₂ is added, thereby lowering the liquidus temperature of the glass. The lower limit of TiO₂ content is preferably more than 0, more preferably 2%, further preferably 3%, still further preferably 5%, and most preferably more than 6%. On the other hand, excessive TiO₂ cannot enter the glass network, resulting in glass devitrification. Hence, the upper limit of TiO₂ content is 10%, preferably 9.5%, more preferably 9%, and most preferably 8.5%.

In such a condition, the total content of ZrO₂, P₂O₅ and TiO₂ is controlled to separate out homogeneous crystals, namely, ZrO₂+P₂O₅+TiO₂ accounts for 1 to 16%. In order to obtain the effect easier, the lower limit of ZrO₂+P₂O₅+TiO₂ is preferably 1%, most preferably 2%; and the upper limit of ZrO₂+P₂O₅+TiO₂ is preferably 16%, more preferably 12%.

In the present invention, to obtain the desired crystalline phase to improve the thermal conductivity and hardness of the glass ceramic substrate, the ratio of the SiO₂ content to the Li₂O content is required to be controlled, namely, the SiO₂/Li₂O ratio is 4 to 10. In order to obtain the effect easier, the lower limit of the SiO₂/Li₂O ratio is preferably 4, more preferably 4.5, and most preferably 5; and the upper limit of the SiO₂/Li₂O ratio is preferably 10, more preferably 9.5, and most preferably 9.

In the present invention, in an attempt to obtain more homogeneous fine crystalline phases in the glass to improve the thermal conductivity and bending strength of the glass ceramic substrate, it is a necessary to control the ratio of the ZrO₂ content to the Li₂O content, that is, ZrO₂/Li₂O ratio is 0 to 0.5, preferably more than 0 but less than 0.35, more preferably more than 0 but less than or equal to 0.30.

In the present invention, in an attempt to obtain the better tempering effect to improve the strength of the glass ceramic substrate, it is necessary to control the ratio of the content of Al₂O₃ content to the total content of LiO₂ and Na₂O, that is, the lower limit of the Al₂O₃/(Na₂O+Li₂O) ratio is preferably 0.5, more preferably 0.7, and most preferably 1; and the upper limit of Al₂O₃/(Na₂O+Li₂O) ratio is preferably 2, more preferably 1.8, and most preferably 1.5.

In the present invention, for realizing the better devitrification resistance, meltability and formability in melting, it is necessary to control the ratio of Li₂O to Na₂O, namely, the Li₂O/Na₂O ratio is 0.8 to 8 preferably. In order to obtain the effect easier, the lower limit of the Li₂O/Na₂O ratio is preferably 0.8, more preferably 1.5, and most preferably 2; and the upper limit of the Li₂O/Na₂O ratio is preferably 8, more preferably 7.5, further preferably 7, and most preferably 6.

B₂O₃ contributes to the decrease of the glass viscosity, the improvement of the glass meltability, formality and toughness, and thus can be added as the optional component. Excessive B₂O₃ can easily lead to decrease of the chemical durability of the glass ceramic, and easily restrain separation of the desired crystals. Hence, the upper limit of B₂O₃ content is preferably 5%, more preferably 4%, and most preferably lower than 2%.

K₂O is an optional component which helps to improve the low-temperature meltability and formality of the glass. But excessive K₂O can easily lead to decrease of the chemical durability and increase of the average linear expansion coefficient. Hence, the upper limit of K₂O content is preferably 5%, more preferably 4%, and most preferably 3%. If the glass ceramic contains K₂O, it is very effective to form the deep compressive stress layer when chemical tempering is conducted by ion exchange. Hence, the lower limit of K₂O content is more than 0, more preferably 0.5%, further preferably 0.8%, and most preferably 1% when chemical tempering is conducted by ion exchange.

MgO is an optional component which facilitates the decrease of the glass viscosity, restrains the devitrification of the bare glass when it is formed, and improves the low-temperature meltability. The lower limit of the MgO content is preferably more than 0. However, if the MgO content is high, the decrease of the devitrification resistance may be caused, and the non-ideal crystals may be obtained to result in the performance decline of the glass ceramic after crystallization. Hence, the upper limit of MgO content is preferably 2%.

ZnO is an optional component which can improve the meltability and chemical stability of the glass, and the lower limit of ZnO content is preferably more than 0; and on the other hand, the upper limit of ZnO content can be controlled to be below 2% to restrain decrease in the devitrification resistance.

CaO is an optional component which helps to the improvement of the glass low-temperature meltability. But excessive CaO can easily lead to decrease of the devitrification resistance. Hence, the upper limit of CaO content is preferably 5%, more preferably 4%, further preferably 3%, and most preferably 1%.

BaO is an optional component which facilitates the improvement of the glass low-temperature meltability. But excessive BaO can easily lead to decrease of the devitrification resistance. Hence, the upper limit of BaO content is preferably 5%, more preferably 4%, further preferably 3%, and most preferably 1%.

FeO can be used as a clarificant, and thus can be contained randomly. But excessive FeO can easily lead to excessive coloring or alloying of platinum for a glass melting plant. Hence, the upper limit of the FeO content is preferably 3%, more preferably 1%.

SnO₂ is an optional component that can be used as a clarificant and can separate out crystals to form a crystal nucleus. Hence, the lower limit of SnO₂ content is preferably more than 0, more preferably 0.01%, and most preferably 0.05%. But excessive SnO₂ can easily lead to decrease of the devitrification resistance of the glass. Hence, the upper limit of SnO₂ content is preferably 2%, more preferably 1%, further preferably 0.4%, and most preferably 0.2%.

SrO is an optional component which helps to improve the glass low-temperature meltability. But excessive SrO can easily lead to decrease of the devitrification resistance. Hence, the upper limit of SrO content is preferably 5%, more preferably 3%, and most preferably 1%.

La₂O₃ is an optional component capable of improving the hardness of the glass ceramic, so that a small amount thereof can be added to lower the glass melting temperature and reduce the liquidus temperature to a certain degree. But excessive La₂O₃ can easily lead to decrease of the devitrification resistance. Hence, the La₂O₃ content is below 10%, preferably below 9%, more preferably more than 0 but less than or equal to 8%.

Y₂O₃ is an optional component of capable of improving the hardness, chemical stability and thermal conductivity of the glass ceramic, so that a small amount thereof can be added to lower the glass melting temperature and reduce the liquidus temperature to a certain degree. But excessive Y₂O₃ can easily lead to decrease of the devitrification resistance. Hence, the Y₂O₃ content is below 10%, preferably below 9%, more preferably more than 0 but less than or equal to 8%.

Nb₂O₅ is an optional component capable of improving the mechanical strength of the glass ceramic. But excessive Nb₂O₅ can easily lead to decrease of the devitrification resistance. Hence, the upper limit of Nb₂O₅ content is preferably 10%, more preferably 8%, and most preferably 5%.

Ta₂O₅ is an optional component capable of improving the mechanical strength of the glass. But excessive Ta₂O₅ can easily lead to decrease of the devitrification resistance. Hence, the upper limit of Ta₂O₅ content is preferably 10%, more preferably 8%, and most preferably 5%.

WO₃ is an optional component capable of improving the mechanical strength of the glass. But excessive WO₃ can easily lead to decrease of the devitrification resistance. Hence, the upper limit of WO₃ content is preferably 5%, more preferably 2%, and most preferably 1%.

In the glass ceramic of the present invention, the clarificant can also contain As₂O₃, Sb₂O₃, CeO₂ and one or more than two selected from a group of F, Cl, NOx and SOx. However, the upper limit of the clarificant content is preferably 5%, more preferably 2%, and most preferably 1%.

The glass ceramics of different colors can be prepared by adding a certain amount of colorant into the glass ceramic of the present invention.

When brown or green glass ceramic is prepared by using NiO and/or Ni₂O₃ as a colorant, the two components can be used separately or together, and contents thereof are respectively not more than 6%, preferably not more than 4%, and more preferably not more than 3%. The lower limits of contents thereof are more than 0.1% respectively. If NiO and Ni₂O₃ are used together, the total amount thereof is generally not more than 6%; if the content is more than 6%, the colorant cannot be dissolved into the glass well.

When Pr₂O₅ is used as a green glass composition colorant separately, the content thereof is not more than 8% generally, preferably not more than 6%, more preferably not more than 5%. Due to the fact that the lower limit of content thereof is more than 0.4%, the glass color is not obvious if the content thereof is lower than 0.4%.

When a blue glass ceramic is prepared by using CoO and/or CO₂O₃ as a colorant, the two colorant components can be used separately or together, and the contents thereof are generally not more than 2% respectively, preferably not more than 1.8%. If the content of each one is more than 2%, the colorant cannot be dissolved into the glass. If CoO and/or CO₂O₃ are used together, the total thereof is not more than 2%. Due to the fact that the lower limit content of each one is more than 0.05%, the glass color is not obvious if the contents thereof are lower than 0.05% respectively.

When a yellow glass ceramic is prepared by using Cu₂O and/or CeO₂ as a colorant, the two colorant components are used separately or together. When Cu₂O is used separately, the content thereof is not more than 4%, preferably not more than 3%; and if the content thereof is more than 4%, the glass is devitrified easily. If CeO₂ is used separately, the content thereof is not more than 4%, preferably not more than 3%; if the content thereof is more than 4%, the vitreous luster is poor. If the two colorants are used together, the total amount thereof is generally not more than 4%, and the lower limit of content thereof is more than 0.5%.

Black and smoky gray glass ceramics are prepared by using Fe₂O₃ separately, or a mixture of Fe₂O₃ and CoO, Fe₂O₃ and CO₂O₃, Fe₂O₃, CoO and NiO, Fe₂O₃, CO₂O₃ and NiO, Fe₂O₃, CoO and CO₂O₃, or Fe₂O₃, CoO, NiO and CO₂O₃ as a colorant. If Fe₂O₃ is used for coloring separately, the content thereof is not more than 8%, preferably not more than 5%, more preferably not more than 3%. CoO and CO₂O₃ can absorb the visible light to deepen the glass blackness. When CoO and CO₂O₃ are mixed with Fe₂O₃ generally, the contents of CoO and CO₂O₃ are not more than 0.3% respectively, and the lower limit of total content thereof is more than 0.2%. NiO can absorb the visible light to deepen the glass blackness, and the content thereof is not more than 1% generally when being used as a mixture.

When a purple glass ceramic is prepared by using MnO₂ a colorant, the content thereof is generally not more than 4%, preferably less than 3%. Due to the fact that the lower limit of content thereof is more than 0.1%, the glass color is not obvious if the content thereof is lower than 0.1%.

When a pink glass ceramic is prepared by using Er₂O₃ as a colorant, the content thereof is not more than 8%, preferably less than 6%. The glass color cannot be further deepened when the content of a rare earth element Er₂O₃ is more than 8% due to its low coloring efficiency, but the glass cost is increased. Due to the fact that the lower limit of content thereof is more than 0.4%, the glass color is not obvious if the content thereof is lower than 0.4%.

A mauve glass composition is prepared by using Nd₂O₃ a colorant, the using content thereof is not more than 8%, preferably lower than 6%. The glass color cannot be further deepened when the content of a rare earth element Nd₂O₃ is more than 8% due to its low coloring efficiency, but the glass cost is increased. Due to that the lower limit of content thereof is more than 0.4%, the glass color is not obvious if the content thereof is lower than 0.4%.

When a red glass ceramic is prepared by using a mixture of Er₂O₃, Nd₂O₃ and MnO₂ as a colorant, Er ions are absorbed at 400-500 nm in the glass, Mn ions are mainly absorbed at 500 nm, Nd ions are mainly absorbed at 580 nm strongly. A red glass composition can be prepared by a mixture of the three. When Er₂O₃ and Nd₂O₃ color the rare earth, the coloring power is rather weak because the usage amounts of Er₂O₃ and Nd₂O₃ are lower than 6% and lower than 4% respectively; the Mn ions are strong in coloring power; the usage amount of MnO₂ is lower than 2%; and the lower limit of total amount of the mixed colorant is more than 0.9%.

When Cr₂O₃ is used as a green glass composition colorant separately, the content thereof is not more than 4% generally, preferably not more than 3%, more preferably not more than 2%. Due to the fact that the lower limit of content is more than 0.2%, the glass color is not obvious if the content thereof is lower than 0.2%.

When V₂O₅ is used as a yellow green glass composition colorant separately, the content thereof is not more than 4% generally, preferably not more than 3%, more preferably not more than 2%. Due to the fact that the lower limit of the content is more than 0.2%, the glass color is not obvious if the content thereof is lower than 0.2%.

The glass ceramic of the present invention can be composed of the above components only, but can be added with other components in a range in which the glass property are not damaged seriously. For instance, TeO₂, Bi₂O₃ and GeO₂ can be added.

The glass ceramic of the present invention has the following features.

The glass ceramic of the present invention is high in devitrification resistance, more particularly, low in liquidus temperature. That is, the upper limit of the liquidus temperature of the glass of the present invention is preferably 1,450° C., more preferably 1,400° C., further preferably 1,380° C., and most preferably 1,320° C. Therefore, even if the molten glass flows out at the low temperature, the devitrification can decrease when the glass is formed from a molten state. Besides, the glass can be formed even if the melting temperature of the glass decreases. Therefore, the degradation of a platinum device and a module can be restrained, energy consumed can be decreased when the glass is formed, and the glass production cost can be lowered.

On the other hand, there is no special limit on the lower limit of the liquidus temperature of the glass of the present invention. The lower limit of liquidus temperature of the glass prepared by the present invention is preferably 1,000° C., more preferably 1,100° C., and most preferably 1,200° C.

The above liquidus temperature is a devitrification resistance indicator. In the Description, the value determined by the following method is used as the liquidus temperature. Firstly, a 30 cc chip glass sample is placed into a 50 ml platinum crucible, and is kept in a completely molten state at 1,500° C. Secondly, the glass is taken out of the furnace for cooling after cooled to a specified temperature and kept for 12 h; crystals are respectively observed on a glass surface and the glass once every 10° C. until 1,200° C., wherein the lowest temperature at which no crystals are found is taken as the liquidus temperature within the specified temperature.

The thermal conductivity of the glass ceramic of the present invention is above 2 W/m·k.

The glass ceramic substrate of the present invention can be subject to ion exchange to form the compressive stress layer for implementing chemical tempering. The compressive stress value thereof is preferably above 300 Mpa when the compressive stress layer is formed. Due to such compressive stress value, the crack extension can be restrained and the mechanical strength can be improved. Hence, when chemical tempering is conducted, the compressive stress layer of the glass ceramic substrate of the present invention has the compressive stress value preferably above 300 Mpa, more preferably above 400 Mpa, and most preferably above 500 Mpa.

The compressive stress layer of the glass ceramic substrate of the present invention has a thickness preferably above 1 μm. Even if deep cracks are generated on the glass ceramic substrate, crack extension or substrate breakage can be restrained due to the fact that the compressive stress layer has such thickness. Hence, the compressive stress layer has the thickness preferably above 1 μm, more preferably above 5 μm, and most preferably above 8 μm.

The glass ceramic substrate of the present invention has a Vickers hardness (Hv) preferably above 600. Due to such hardness, the scratches can be restrained and the mechanical strength can be improved. The glass ceramic of the present invention has the Vickers hardness (Hv) preferably above 600, more preferably above 650, and most preferably above 700.

The glass ceramic substrate of the present invention cannot break preferably even if a 32 g steel ball falls to the substrate from a height of 500 mm. With such impact resistance, it can bear the impact caused by falling down or collision when being used as a protection component. Hence, the glass ceramic substrate does not break when the 32 g steel ball falls down preferably from a height above 500 mm, more preferably above 650 mm, and most preferably above 800 mm.

A three-point bending strength of the glass ceramic substrate of the present invention is preferably 450 Mpa. Due to such three-point bending strength, the glass will not be broken while bearing the sufficient pressure. Hence, the three-point bending strength is preferably above 450 Mpa, more preferably above 600 Mpa, and most preferably above 800 Mpa.

The glass ceramic of the present invention can be prepared by the following methods: homogeneously mixing raw materials by component proportion ranges; placing the homogeneous mixture into a platinum or quartz crucible; melting in an electric furnace or a gas furnace for 5 to 24 h in a temperature range from 1,250° C. to 1,550° C. based on the melting difficulty of the glass composition; after stirring homogeneously, cooling to a proper temperature and casting to a mold, and finally cooling.

The bare glass of the glass ceramic of the present invention can be formed by virtue of a well-known method.

The bare glass of the glass ceramic of the present invention is crystallized after formed or processed, and the crystals are separated inside the glass homogeneously. The crystallization treatment can be conducted through one stage or two stages, but two stages are preferred. A nucleus formation technology is conducted at a first temperature, and a crystal growth technology is conducted at a second temperature higher than that of the nucleus formation technology. The crystallization treatment conducted at the first temperature is called the first crystallization treatment, and the crystallization treatment conducted at the second temperature is called the second crystallization treatment.

For making the glass ceramic have the desired physical properties, the preferred thermal treatment condition is as follows:

The nucleus formation and crystal growth technologies can be conducted continuously by virtue of the crystallization treatment at one stage. That is, the glass ceramic is kept at the thermal treatment temperature for a certain period of time after rise to the specified crystallization treatment temperature, and then cooled. The crystallization treatment temperature is preferably 500 to 700° C., more preferably 550 to 680° C. in an order to separate the desired crystalline phase. The holding time is preferably 0 to 8 h, more preferably 1 to 6 h at the crystallization treatment temperature.

When the crystallization treatment is conducted through the above two stages, the first temperature is preferably 500 to 700° C., and the second temperature is preferably 650 to 850° C. The holding temperature is preferably 0 to 24 h, most preferably 2 to 15 h at the first temperature. The holding temperature is preferably 0 to 10 h, most preferably 2 to 5 h at the second temperature.

The above holding time as 0 min refers to that cooling or heating is started after the temperature thereof is reached for less than 1 min.

The bare glass or the glass ceramic of the present invention can be made into the glass forming body with the aid of a grinding or polishing method. The glass ceramic substrate can be prepared by taking the glass ceramic of the present invention as a substrate by means of processing the glass forming body to be a sheet shape. However, the method for making the glass forming body is not limited to these methods.

The glass ceramic substrate of the present invention can be prepared into various shapes at a certain temperature by a hot bending or pressing method, and the hot bending and pressing temperatures are lower than the crystallization temperature. However, the method for making the glass in various shapes is not limited to these methods.

For the glass ceramic of the present invention, high strength can be obtained by the formation of the compressive stress layer, in addition to separating the crystals to improve the mechanical property. The method for forming the compressive stress layer includes a chemical tempering method, that is, the compressive stress layer is formed on the surface layer by the exchange reaction between alkaline components on the surface layer of the glass ceramic substrate and alkaline components with the radius more than the former. Besides, there is an ion implantation method capable of injecting ions into the surface layer of the glass ceramic substrate and a hot tempering method capable of heating the glass ceramic substrate, and then rapidly cooling the same.

The glass ceramic and the glass ceramic substrate of the present invention are applicable to making protective cover plates for such portable electronic devices as mobile phones, tablet PCs and watches, thereby being applicable to mobile phones, tablet PCs and other portable electronic devices. Meanwhile, the glass ceramic and the glass ceramic substrate of the present invention are also applicable to various optical instruments.

The embodiments (Tables 1 to 8) of the present invention are prepared by the following methods: firstly, selecting the respective corresponding oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, hydroxides and metaphosphoric acid compounds as various component components; homogeneously mixing raw materials by component proportion ranges; placing the homogeneous mixture into a platinum or quartz crucible; melting in an electric furnace or a gas furnace for 5 to 24 h in a temperature range from 1,250° C. to 1,550° C. based on the melting difficulty of the glass composition; after stirring homogeneously, cooling to a proper temperature and casting to a mold, and finally cooling to obtain the bare glass slowly.

With respect to the obtained bare glass, the glass ceramic is made for nucleus formation and crystallization by the thermal treatment at the first stage or the second stage respectively. Embodiments 15, 18, 20 and 22 are subject to thermal treatment at the first stage, and other embodiments are subject to thermal treatment at the second stage. In Tables 1 to 8, the thermal treatment conditions at the first stage are recorded in the column “nucleus formation technology”, the thermal treatment conditions at the second stage are recorded in the column “crystallization technology”, and the thermal treatment temperatures and the holding time at the temperatures thereof are shown in the tables.

For the crystalline phase of the glass ceramic before chemical tempering in the embodiments, the crystalline phase of the glass ceramic substrate is analyzed by an X-ray diffraction analysis apparatus with the help of an angle of displaying a peak value on an X-ray diffraction pattern.

The prepared glass ceramic is cut and ground to obtain 36×29×0.7 mm sheets; opposed faces are polished in parallel; and then the polished glass ceramic is soaked into KNO₃ molten salt for chemical tempering to obtain the glass ceramic substrate. The temperature and time for soaking the molten salt are shown in the column “chemical tempering conditions” in the table.

A compressive stress value of the surface of the glass ceramic substrate chemically tempered and the thickness of the compressive stress layer are determined by a glass surface stress gauge FSM-6000. The determination condition is that calculation is conducted based on a refractive index of the sample as 1.53 and an elastic constant of 28.5[(nm/cm)/Mpa].

The Vickers hardness of the glass ceramic substrate in the embodiments is expressed by a load (N) of a diamond square pyramid pressure head divided by a surface area (mm²) calculated by an indentation length. The head with an 136° angle between the opposed surfaces is pressed into a pyramid shape on a test surface. The calculation is conducted when a test load is 100 (N) and the holding time is 15 s. With regard to the embodiments having “the chemical tempering conditions”, the calculation is conducted for the chemically tempered substrate.

The ball falling height in the embodiments indicates the maximum ball falling height capable of bearing the impact under the condition that the substrate does not break when two surfaces of the 36×29×0.8 mm substrate are polished and then placed on a rubber sheet to make the 32 g steel ball fall from the specified height. To be specific, the test is conducted when the ball falling height is 650 mm. The height is changed as 700 mm, 750 mm, 800 mm, 850 mm or 900 mm without breaking. With regard to the embodiments having “the chemical tempering conditions”, the substrate chemically tempered is used as a test object. The test data recorded as 900 mm in the embodiments indicates that the substrate bears the impact without breaking even if the steel ball falls down to the substrate from a height of 900 m.

The three-point bending strength of the 36×29×0.7 mm glass in Tables 1 to 8 is tested by a microcomputer controlled electronic universal testing machine CMT6502 based on standard ASTM C 158-2002.

The thermal conductivity of the glass ceramic in Tables 1 to 8 is determined by a thermal conductivity test instrument LFA447. Based on such determination conditions as room temperature of 25° C. and sample specification of Φ12.7 mm×1.5 mm, Glass. The Method for Measuring Thermal Conductivity (JC/T675-1997) is conducted.

The color in the embodiments is the color of a glass sheet 36×29×0.8 mm visually observed.

TABLE 1
Component	Embodiments
(wt %)	1	2	3	4	5	6	7	8	9	10
SiO2	60	61	62	63	64	65	66	67	68	69
Al2O3	20	15	16	17	18	19	14	13	13	12
Li2O	8	9	8	11	12	10	14	15	13	12
Na2O	5	3	3	5	3	2	2	4	3	6
P2O5	2	2	2	3	2	1			1
ZrO2	3	2	2	1	1	1	1	1	1	1
TiO2	2		2			2	1		1
B2O3		2	1
K2O		3	1.5
MgO		1	0.5				1
ZnO		2	2				1
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	7.5	6.8	7.8	5.7	5.3	6.5	4.7	4.5	5.2	5.8
Al2O3/(Na2O +	1.5	1.3	1.5	1.1	1.2	1.6	0.9	0.7	0.8	0.7
Li2O)
Li2O/Na2O	1.6	3	2.7	2.2	4	5	7	3.8	4.3	2
ZrO2 + P2O5 +	7	4	6	4	3	4	2	1	3	1
TiO2
ZrO2/Li2O	0.38	0.22	0.25	0.09	0.08	0.10	0.07	0.07	0.08	0.38
Liquidus	1230° C.	1240° C.	1220° C.	1240° C.	1240° C.	1240° C.	1250° C.	1250° C.	1250° C.	1250° C.
temperature
(° C.)
Nucleus	550° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.
formation	24 h	10 h	6 h	10 h	10 h	6 h	10 h	10 h	6 h	10 h
technology
Crystallization	690° C.	690° C.	690° C.	710° C.	710° C.	710° C.	730° C.	730° C.	730° C.	750° C.
technology	2 h	6 h	10 h	2 h	3 h	5 h	2 h	3 h	5 h	3 h
Crystalline	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5
phase	quartz	quartz	quartz	Na2Si2O5,	quartz	quartz	quartz	quartz	quartz	and
	and	and	and	LiAlSi2O6,	and	and	and	and	and	quartz
	quartz	quartz	quartz	Li3PO3	quartz	quartz	quartz	quartz	quartz	and
	solid	solid	solid		solid	solid	solid	solid	solid	quartz
	solution	solution	solution		solution	solution	solution	solution	solution	solid
	and	and	and		and	and	and	and	and	solution
	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10		LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
tempering	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	560	530	520	—	535	525	500	520	530	—
(MPa)
Stress depth	14	13	12	—	13	12	10	12	13	—
(μm)
Vickers	700	702	703	704	712	715	722	725	724	720
hardness
(kgf/mm2)
Three-point	802	810	830	833	840	842	852	860	862	870
bending
strength (MPa)
Ball falling	750	750	750	850	850	900	900	950	900	850
height (mm)
Thermal	2.3	2.5	2.5	2.2	2.3	2.6	2.7	2.3	2.5	2.4
conductivity
(W/(mK)
Color	Trans-	Trans-	Trans-	Milky	Trans-	Trans-	Trans-	Trans-	Trans-	White
	parent	parent	parent		parent	parent	parent	parent	parent

TABLE 2
Component	Embodiments
(wt %)	11	12	13	14	15	16	17	18	19	20
SiO2	70	71	72	73	74	75	76	77	78	79
Al2O3	12	11	10	7	10	9	9	8	6	6
Li2O	10	11	10	11	8	9.5	10.5	10	13	10
Na2O	3	4	7	4	6	2	1.5	2	2	4
P2O5	1	2		2	1	1
ZrO2	3	1	1	2	1	3.5	1	2	1	1
TiO2	1			1			2	1
B2O3
K2O
MgO
ZnO
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	7	6.5	7.2	6.6	9.3	7.9	7.2	7.7	6	7.9
Al2O3/(Na2O + Li2O)	0.9	0.7	0.6	0.5	0.7	0.8	0.8	0.7	0.4	0.4
Li2O/Na2O	3.3	2.8	1.4	2.8	1.3	4.8	7	5	6.5	2.5
ZrO2 + P2O5 + TiO2	5	3	1	5	2	4.5	3	3	1	1
ZrO2/Li2O	0.30	0.09	0.10	0.18	0.13	0.37	0.10	0.20	0.08	0.10
Liquidus	1250° C.	1250° C.	1260° C.	1270° C.	1250° C.	1250° C.	1250° C.	1250° C.	1280° C.	1280° C.
temperature
(° C.)
Nucleus	600° C.	600° C.	590° C.	600° C.	770° C.	590° C.	600° C.	790° C.	590° C.	810° C.
formation	10 h	6 h	10 h	10 h	4 h	10 h	10 h	5 h	10 h	1 h
technology
Crystallization	750° C.	750° C.	770° C.	770° C.		790° C.	790° C.		810° C.
technology	3 h	3 h	4 h	4 h		5 h	5 h		1 h
Crystalline	Li2Si2O5	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,
phase		and	Na2Si2O5,	and	Na2Si2O5,	and	Li2TiO3,	Li2TiO3,	and	and
		quartz	and	quartz	and	quartz	and	and	quartz	quartz
		solid	quartz	solid	quartz	solid	quartz	quartz	solid	solid
		solution	solid	solution	solid	solution	solid	solid	solution	solution
			solution		solution		solution	solution
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
tempering	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	—	—	—	—	—	—	—	—	—	—
(MPa)
Stress depth	—	—	—	—	—	—	—	—	—	—
(μm)
Vickers	724	725	728	730	731	735	736	746	745	745
hardness
(kgf/mm2)
Three-point	872	876	880	882	886	890	900	901	904	905
bending
strength (MPa)
Ball falling	850	850	800	800	800	750	750	750	750	750
height (mm)
Thermal	2.3	2.2	2.1	2.3	2.1	2.4	2.4	2.2	2.3	2.2
conductivity
(W/(mK)
Color	Milky	Milky	White	Milky	Milky	Milky	Milky	Milky	White	White
	white	white		white	white	white	white	white

TABLE 3
Component	Embodiments
(wt %)	21	22	23	24	25	26	27	28	29	30
SiO2	65	65.5	67	66.5	67	67.5	68	68.5	69	69.5
Al2O3	8	8	8	7	7	10	7	6	7	6
Li2O	15	9	10	10	10	10	10	10	10	11
Na2O	4	8	7	7	7	5	5	5	5	6
P2O5	1		2	1		2			2	1
ZrO2	1	2	1	1	1	2	1	2	2	1
TiO2			2	1	1		1		1
B2O3	5					0.5
K2O		5	1	0.5	1	1	0.5		2
MgO		1	1	1	1	1			1
ZnO		1	1			1	0.5	0.5	1	0.5
CaO										5
BaO
FeO
SnO2	1	0.5
SrO				5
La2O3
Y2O3
Nb2O5								8
Ta2O5							7
WO3					5
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	4.3	7.3	6.7	6.7	6.7	6.8	6.8	6.9	6.9	6.3
Al2O3/(Na2O + Li2O)	0.4	0.5	0.5	0.4	0.4	0.7	0.5	0.4	0.5	0.4
Li2O/Na2O	3.8	1.1	1.4	1.4	1.4	2.0	2	2	2.0	1.8
ZrO2 + P2O5 + TiO2	2	2	5.0	3	2	4.0	2	2	5.0	2
ZrO2/Li2O	0.07	0.22	0.10	0.10	0.10	0.20	0.10	0.20	0.20	0.09
Liquidus	1290° C.	1280° C.	1280° C.	1290° C.	1290° C.	1280° C.	1280° C.	1290° C.	1290° C.	1290° C.
temperature (° C.)
Nucleus	590° C.	650° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.
formation	6 h	10 h	6 h	10 h	10 h	6 h	10 h	10 h	6 h	10 h
technology
Crystallization	690° C.		690° C.	710° C.	710° C.	710° C.	730° C.	730° C.	730° C.	730° C.
technology	2 h		10 h	2 h	3 h	5 h	2 h	3 h	5 h	3 h
Crystalline	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,
phase	quartz	Na2Si2O5	Na2Si2O5	Na2Si2O5	Na2Si2O5	quartz	quartz	quartz	quartz	Na2Si2O5
	and					and	and	and	and
	quartz					quartz	quartz	quartz	quartz
	solid					solid	solid	solid	solid
	solution					solution	solution	solution	solution
	and					and	and	and	and
	LiAlSi4O10					LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
strengthening	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	550	—	—	—	525	510	500	512	527	—
(MPa)
Stress depth	14	—	—	—	13	12	10	12	13	—
(μm)
Vickers	700	706	706	710	712	715	721	720	720	720
hardness
(kgf/mm2)
Three-point	850	750	760	755	756	860	855	863	865	820
bending strength
(MPa)
Ball falling	800	700	700	700	700	800	850	850	850	800
height (mm)
Thermal	2.5	2.1	2.2	2.2	2.1	2.6	2.7	2.5	2.5	2.7
conductivity
(W/(mK)
Color	Trans-	White	White	White	White	Trans-	Trans-	Trans-	Trans-	Trans-
	parent					parent	parent	parent	parent	parent

TABLE 4
Component	Embodiments
(wt %)	31	32	33	34	35	36	37	38	39	40
SiO2	70	70.5	71	71.5	72	72.5	73	73.5	74	74.5
Al2O3	6	5	5	5	5	4	4	4	4	4
Li2O	11	11	12	12	12	13	13	14	14	15
Na2O	6	6	6	5	5	5	5	5	5	4
P2O5						1		0
ZrO2	2	1	2	1	2	1	2	2	2	2
TiO2		1		1
B2O3		4				3
K2O				3	2			1
MgO		1	1		1			0.5
ZnO			1	0.5	0.5	0.5
CaO					0.5
BaO	5			1			3		1
FeO		0.5	2							0.5
SnO2
SrO
La2O3
Y2O3
Nb2O5
Ta2O5
WO3
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	6.4	6.4	5.9	6	6	5.6	5.6	5.3	5.3	5
Al2O3/(Na2O + Li2O)	0.4	0.3	0.3	0.3	0.3	0.2	0.2	0.2	0.2	0.2
Li2O/Na2O	1.8	1.8	2.0	2.4	2.4	2.6	2.6	2.8	2.8	3.8
ZrO2 + P2O5 + TiO2	2	2	2	2	2	2	2	2	2	3
ZrO2/Li2O	0.18	0.09	0.17	0.08	0.17	0.08	0.15	0.14	0.14	0.13
Liquidus	1290° C.	1300° C.	1300° C.	1300° C.	1300° C.	1320° C.	1320° C.	1320° C.	1320° C.	1320° C.
temperature (° C.)
Nucleus	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.
formation	10 h	6 h	10 h	10 h	6 h	10 h	10 h	6 h	10 h	10 h
technology
Crystallization	730° C.	715° C.	720° C.	715° C.	720° C.	730° C.	720° C.	715° C.	710° C.	730° C.
technology	4 h	5 h	6 h	2 h	2.5 h	3 h	4 h	6 h	6 h	2 h
Crystalline phase	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,
	Na2Si2O5	Na2Si2O5	Na2Si2O5	quartz	quartz	quartz	quartz	quartz	quartz	quartz
				and	and	and	and	and	and	and
				quartz	quartz	quartz	quartz	quartz	quartz	quartz
				solid	solid	solid	solid	solid	solid	solid
				solution	solution	solution	solution	solution	solution	solution
				and	and	and	and	and	and	and
				LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
tempering	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	—	—	—	—	—	—	—	—	—	—
(MPa)
Stress depth (μm)	—	—	—	—	—	—	—	—	—	—
Vickers hardness	721	710	715	717	718	723	720	710	710	720
(kgf/mm2)
Three-point	825	815	821	845	847	850	860	855	859	870
bending strength
(MPa)
Ball falling	750	750	750	850	850	850	800	800	800	850
height (mm)
Thermal	2.4	2.3	2.3	2.5	2.6	2.5	2.7	2.5	2.6	2.3
conductivity
(W/(mK)
Color	Milky	Milky	Milky	Trans-	Trans-	Trans-	Trans-	Trans-	Trans-	Trans-
	white	white	white	parent	parent	parent	parent	parent	parent	parent

TABLE 5
Component	Embodiments
(wt %)	41	42	43	44	45	46	47	48	49	50
SiO2	63.7	64	65	66.2	63	64	65	66	69	67.5
Al2O3	7.8	7.5	8	7	6.5	6.8	6.7	6	6	5.8
Li2O	14	8.8	8	10	9.5	9	9	10	7	10.7
Na2O	3.5	7.8	5	6	6	3.5	4.8	4	5	5.5
P2O5	1	0.4	2	1		1	1		0.8	1
ZrO2	2	2	2	1	1	1	1	1.5	1	1
TiO2			2	1	1	1	1	1
B2O3	5
K2O		5	2	1	1		0.5
MgO		1		1	1	0.5
ZnO		1	0.5	0.3			0.5	0.5		0.5
CaO					1					5
BaO
FeO
SnO2	1	0.5
SrO				5
La2O3						8
Y2O3			5						8
Nb2O5								8
Ta2O5							7
WO3					5
NiO	2	1				0.1			0.1
Ni2O3		1
CoO			0.5			0.1			0.1
Co2O3				0.5
Fe2O3					5	5	3.5	3	3
MnO2										3
Er2O3
Nd2O3
Cu2O
Pr2O5
CeO2
V2O5
Cr2O3
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	4.6	7.3	8.1	6.6	6.6	7.1	7.2	6.6	9.9	6.3
Al2O3/(Na2O + Li2O)	0.4	0.5	0.6	0.4	0.4	0.5	0.5	0.4	0.5	0.4
Li2O/Na2O	4.0	1.1	1.6	1.7	1.6	2.6	1.9	2.5	1.4	1.9
ZrO2 + P2O5 + TiO2	3	2.4	6	3	2	3	3	2.5	1.8	2
ZrO2/Li2O	0.14	0.23	0.25	0.10	0.11	0.11	0.11	0.15	0.14	0.09
Liquidus	1280° C.	1280° C.	1260° C.	1280° C.	1290° C.	1260° C.	1260° C.	1280° C.	1260° C.	1290° C.
temperature (° C.)
Nucleus	590° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.
formation	6 h	10 h	6 h	10 h	10 h	6 h	10 h	10 h	6 h	10 h
technology
Crystallization	690° C.	690° C.	690° C.	710° C.	710° C.	710° C.	730° C.	730° C.	730° C.	730° C.
technology	2 h	6 h	10 h	2 h	3 h	5 h	2 h	3 h	5 h	3 h
Crystalline phase	Li2Si2O5	Li2Si2O5,	Li2Si2O5,	Li2Si2O	Li2Si2O5,	Li2Si2O5	Li2Si2O5	Li2Si2O5	Li2Si2O5	Li2Si2O5,
		quartz	quartz		quartz					quartz
		and	and		and					and
		quartz	quartz		quartz					quartz
		solid	solid		solid					solid
		solution	solution		solution					solution
		and	and		and					and
		LiAlSi4O10	LiAlSi4O10		LiAlSi4O10					LiAlSi4O10
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
tempering	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	—	—	—	—	—	—	—	—	—	—
(MPa)
Stress depth (μm)	—	—	—	—	—	—	—	—	—	—
Vickers hardness	—	—	—	—	—	—	—	—	—	—
(kgf/mm2)
Three-point	800	950	850	845	855	84	850	825	823	830
bending strength
(MPa)
Ball falling	800	800	800	750	750	750	700	700	700	700
height (mm)
Thermal	2.4	2.4	2.3	2.3	2.3	2.5	2.6	2.6	2.5	2.3
conductivity
(W/(mK)
Color	Green	Green	Blue	Blue	Black	Black	Black	Black	Black	Violet

TABLE 6
Component	Embodiments
(wt %)	51	52	53	54	55	56	57	58	59	60
SiO2	64.5	65	71	68	66.5	71	67.5	72	70	70
Al2O3	5.5	4.5	5	5	4.5	4	5	6	6	4
Li2O	10	10	10	8	9.5	10	8	8	12	15
Na2O	5.5	5.5	4	5	4.5	5	5	8	5	4
P2O5		0.8			1	0.5	1.5	2	1
ZrO2	2	1	2	1	1	2	2	1	2	3
TiO2		0.2		1	1	2				2
B2O3		3.5				3
K2O				1	2			1
MgO		1	1		1
ZnO			1	0.5	0.5	0.5
CaO					0.5
BaO	4.5			1			3		1
FeO		0.5	2							1
SnO2
SrO
La2O3
Y2O3
Nb2O5
Ta2O5
WO3
NiO
Ni2O3
CoO
Co2O3
Fe2O3
MnO2				1.5	2
Er2O3	8			4	3
Nd2O3		8	4	4	3
Cu2O						2
Pr2O5							8
CeO2								2
V2O5									3
Cr2O3										1
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	6.5	6.5	7.1	8.5	7.0	7.1	8.4	9.0	5.8	4.7
Al2O3/(Na2O + Li2O)	0.4	0.3	0.4	0.4	0.3	0.3	0.4	0.4	0.4	0.2
Li2O/Na2O	1.8	1.8	2.5	1.6	2.1	2	1.6	1	2.4	3.8
ZrO2 + P2O5 + TiO2	2	2	2	2	2	4.5	3.5	3	3	5
ZrO2/Li2O	0.20	0.10	0.20	0.13	0.11	0.20	0.25	0.13	0.17	0.20
Liquidus	1290° C.	1300° C.	1290° C.	1280° C.	1290° C.	1300° C.	1280° C.	1280° C.	1290° C.	1350° C.
temperature (° C.)
Nucleus	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.	600° C.	590° C.	600° C.
formation	10 h	6 h	10 h	10 h	6 h	10 h	10 h	6 h	10 h	10 h
technology
Crystallization	730° C.	715° C.	720° C.	715° C.	720° C.	730° C.	720° C.	715° C.	710° C.	730° C.
technology	4 h	5 h	6 h	2 h	2.5 h	3 h	4 h	6 h	6 h	2 h
Crystalline phase	Li2Si2O5	Li2Si2O5,	Li2Si2O5	Li2Si2O5,	Li2Si2O5	Li2Si2O5	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,
		quartz		quartz			quartz	quartz	quartz	quartz
		and		and			and	and	and	and
		quartz		quartz			quartz	quartz	quartz	quartz
		solid		solid			solid	solid	solid	solid
		solution		solution			solution	solution	solution	solution
		and		and			and	and	and	and
		LiAlSi4O10		LiAlSi4O10			LiAlSi4O10	LiAlSi4O10	LiAlSi4O10	LiAlSi4O10
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
tempering	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	—	—	—	—	—	—	—	—	—	—
(MPa)
Stress depth (μm)	—	—	—	—	—	—	—	—	—	—
Vickers hardness	—	—	—	—	—	—	—	—	—	—
(kgf/mm2)
Three-point	835	832	823	833	825	850	860	900	850	833
bending strength
(MPa)
Ball falling	700	750	750	750	750	700	750	750	800	700
height (mm)
Thermal	2.6	2.5	2.6	2.7	2.8	2.6	2.8	2.3	2.5	2.5
conductivity
(W/(mK)
Color	Pink	Mauve	Mauve	Red	Red	Yellow	Grass	Yellow	Yellow	Green
							green		green

TABLE 7
Component	Embodiments
(wt %)	61	62	63	64	65	66	67	68	69	70
SiO2	70	69.5	70	70	71	70	70	70	69.5	70
Al2O3	8	7.5	8	7	7.5	7	7	7	9	9
Li2O	8	8.5	8.5	9	9	9.5	10	9	9.5	10
Na2O	6	6	5	3	5.5	6	5	4	2	2
P2O5	2	2	2	2	2	2	2	1	2	2
ZrO2	1	2	1	1	1	1	1	2	2	1
TiO2
B2O3					1
K2O	1		0.5
MgO	1	0.5			1
ZnO	1
CaO						0.5
BaO										1
SrO									1
La2O3	2	4	5	8					2	3
Y2O3					2	4	5	7	3	2
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	8.8	8.2	8.2	7.8	7.9	7.4	7	7.8	7.3	7
Al2O3/(Na2O + Li2O)	0.6	0.5	0.6	0.6	0.5	0.5	0.5	0.5	0.8	0.8
Li2O/Na2O	1.3	1.4	1.7	3	1.6	1.6	2	2.3	4.8	5
ZrO2 + P2O5 + TiO2	3	4	3	3	3	3	3	3	4	3
ZrO2/Li2O	0.13	0.24	0.12	0.11	0.11	0.11	0.10	0.22	0.21	0.10
Liquidus	1260° C.	1260° C.	1240° C.	1220° C.	1250° C.	1260° C.	1260° C.	1230° C.	1220° C.	1220° C.
temperature
(° C.)
Nucleus	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.
formation	6 h	8 h	10 h	6 h	8 h	10 h	6 h	8 h	10 h	8 h
technology
Crystallization	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.
technology	2 h	2 h	2 h	2 h	2 h	2 h	2 h	2 h	2 h	2 h
Crystalline	Li2Si2O5	Li2Si2O5	Li2Si2O5	Li2Si2O5,	Li2Si2O5	Li2Si2O5	Li2Si2O5	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,
phase				quartz				quartz	quartz	quartz
				and				and	and	and
				quartz				quartz	quartz	quartz
				solid				solid	solid	solid
				solution				solution	solution	solution
				and				and	and	and
				LiAlSi4O10				LiAlSi4O10	LiAlSi4O10	LiAlSi4O10
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
strengthening	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface	—	—	—	710	—	—	—	730	650	660
stress (MPa)
Stress depth	—	—	—	12	—	—	—	13	10	10
(μm)
Vickers	719	736	742	751	724	736	742	755	735	739
hardness
(kgf/mm2)
Three-point	813	809	818	854	802	824	828	866	832	843
bending
strength
(MPa)
Ball falling	850	850	850	950	800	800	800	950	850	850
height (mm)
Thermal	2.1	2.1	2.2	2.4	2.3	2.2	2.3	2.4	2.6	2.5
conductivity
(W/(mK)
Color	White	White	White	Trans-	White	White	White	Trans-	Trans-	Trans-
				parent				parent	parent	parent

TABLE 8
	Embodiments
Component (wt %)	71	72	73	74	75	76	77	78	79	80
SiO2	65	68	67	68	69	70	67	65	67	67
Al2O3	8	6	7	6	6.5	5	7	5	5	9
Li2O	8	8.5	8.5	9	9	9.5	10	9	9	9
Na2O	6	6	5	3	5.5	6	5	4	4	4
P2O5	2	2	2	2	2	2	2	1		1
ZrO2	1	2	1	1	1	1	1	2	2	1
TiO2	3	3	4	5	5	6	6	7	8	9
B2O3					1
K2O	1		0.5					2	1
MgO	1	0.5			1			1	1
ZnO	1							1	1
CaO						0.5
BaO								1
SrO								1
La2O3	1	4	5	3					2
Y2O3	3			3			2	1
Total	100	100	100	100	100	100	100	100	100	100
SiO2/Li2O	8.1	8	7.9	7.6	7.7	7.4	6.7	7.2	7.4	7.4
Al2O3/(Na2O + Li2O)	0.6	0.4	0.5	0.5	0.4	0.3	0.5	0.4	0.4	0.7
Li2O/Na2O	1.3	1.4	1.7	3	1.6	1.6	2	2.3	2.3	2.3
ZrO2 + P2O5 + TiO2	6	7	7	8	8	9	9	10	10	11
ZrO2/Li2O	0.13	0.24	0.12	0.11	0.11	0.11	0.10	0.22	0.22	0.11
Liquidus	1100	1080	1060	1030	1020	1040	1050	1090	1100	1150
temperature (° C.)
viscosity at	6250	9140	13000	19200	21400	17100	15000	7300	5360	3500
liquidus
temperature (P)
Nucleus formation	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.	550° C.
technology	6 h	8 h	10 h	6 h	8 h	10 h	6 h	8 h	10 h	8 h
Crystallization	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.	690° C.
technology	2 h	2 h	2 h	2 h	2 h	2 h	2 h	2 h	2 h	2 h
Crystalline phase	Li2Si2O5	Li2Si2O5	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,	Li2Si2O5,
			Li2TiO3	Li2TiO3	Li2TiO3	Li2TiO3	Li2TiO3	Li2TiO3	Li2TiO3	Li2TiO3
Chemical	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.	430° C.
strengthening	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h	8 h
conditions
Surface stress	—	—	—	710	—	—	—	730	650	660
(MPa)
Stress depth (μm)	—	—	—	12	—	—	—	13	10	10
Vickers hardness	722	743	745	760	712	705	721	723	731	716
(kgf/mm2)
Three-point	817	820	818	860	800	817	830	880	885	825
bending strength
(MPa)
Ball falling height	850	850	850	950	850	850	850	900	850	850
(mm)
Thermal	2.1	2.1	2.1	2.3	2.3	2.2	2.3	2.3	2.5	2.4
conductivity
(W/(mK)
Color	White	White	White	Trans-	White	White	White	Trans-	Trans-	Trans-
				parent				parent	parent	parent

As can be seen in the above embodiments, the glass ceramic of the present invention has the thermal conductivity above 2 W/ink at room temperature (25° C.), thereby having high thermal conductivity, and good bending strength, hardness and resistance to damage. Meanwhile, the glass ceramic of the present invention can also have individualized colors. The glass ceramic or the substrate of the present invention is applicable to such protective components as portable electronic devices and optical devices, especially as back cover plate.

Claims

1. A glass ceramic, containing the following components by wt %: 60 to 80% of SiO2; 4 to 20% of Al2O3; 0 to 15% of Li2O; more than 0 but less than or equal to 12% of Na2O; 0 to 5% of K2O; more than 0 but less than or equal to 5% of ZrO2; 0 to 5% of P2O5; and 0 to 10% of TiO2, wherein a crystalline phase contains at least one selected from R2SiO3, R2Si2O5, R2TiO3, R4Ti5O12, R3PO3, RAlSi2O6, RAlSiO4O10, R2Al2Si2O8, R4Al4Si5O18, quartz and quartz solid solution, and R is at least one selected from Li, Na and K.

2. The glass ceramic according to claim 1, further containing 0 to 5% of B2O3; and/or 0 to 2% of MgO; and/or 0 to 2% of ZnO; and/or 0 to 5% of CaO; and/or 0 to 5% of BaO; and/or 0 to 3% of FeO; and/or 0 to 2% of SnO2; and/or 0 to 5% of SrO; and/or 0 to 10% of La2O3; and/or 0 to 10% of Y2O3; and/or 0 to 10% of Nb2O5; and/or 0 to 10% of Ta2O5; and/or 0 to 5% of WO3.

3. A glass ceramic, containing the following components by wt %: 60 to 80% of SiO2; 4 to 20% of Al2O3; 0 to 15% of Li2O; more than 0 but less than or equal to 12% of Na2O; more than 0 but less than or equal to 5% of ZrO2; 0 to 5% of P2O5; 0 to 10% of TiO2; 0 to 5% of B2O3; 0 to 5% of K2O; 0 to 2% of MgO; 0 to 2% of ZnO; 0 to 5% of CaO; 0 to 5% of BaO; 0 to 3% of FeO; 0 to 2% of SnO2; 0 to 5% of SrO; 0 to 10% of La2O3; 0 to 10% of Y2O3; 0 to 10% of Nb2O5; 0 to 10% of Ta2O5; 0 to 5% of WO3; and 0 to 5% of a clarificant, wherein a crystalline phase contains at least one selected from R2SiO3, R2Si2O5, R2TiO3, R4Ti5O12, R3PO3, RAlSi2O6, RAlSiO4O10, R2Al2Si2O8, R4Al4Si5O18, quartz and quartz solid solution, and R is at least one selected from Li, Na and K.

4. The glass ceramic according to claim 1, wherein SiO2 accounts for 65 to 78%; and/or Al2O3 accounts for 5 to 18%; and/or 0 to 12% of Li2O; and/or Na2O accounts for 0.5 to 10%; and/or ZrO2 accounts for 0.4 to 3%; and/or P2O5 accounts for 0.4 to 3%; and/or B2O3 accounts for 0 to 4%; and/or K2O accounts for 0.5 to 4%; and/or MgO accounts for more than 0 but less than or equal to 2%; and/or ZnO accounts for more than 0 but less than or equal to 2%; and/or CaO accounts for 0 to 4%; and/or BaO accounts for 0 to 4%; and/or FeO accounts for 0 to 1%; and/or SnO2 accounts for 0.01 to 1%; and/or SrO accounts for 0 to 3%; and/or La2O3 accounts for 0 to 9%; and/or Y2O3 accounts for 0 to 9%; and/or Nb2O5 accounts for 0 to 8%; and/or Ta2O5 accounts for 0 to 8%; and/or WO3 accounts for 0 to 2%; and/or the clarificant contains As2O3, Sb2O3 and CeO2 and at least one selected from the group consisting of F, Cl, NOx and SOx with a content of 0 to 5%.

5. The glass ceramic according to claim 1, wherein SiO2/Li2O ratio is 4 to 10; and/or ZrO2/Li2O ratio is 0 to 0.5; and/or Al2O3/(Na2O+Li2O) ratio is 0.5 to 2; and/or Li2O/Na2O ratio is 0.8 to 8.

6. The glass ceramic according to claim 1, wherein SiO2 accounts for 68 to 75%; and/or Al2O3 accounts for 6 to 15%; and/or Li2O accounts for 6 to 10%; and/or Na2O accounts for 2 to 8%; and/or ZrO2 accounts for 0.8 to 2%; and/or P2O5 accounts for 0.8 to 2%; and/or TiO2 accounts for 1 to 4%; and/or B2O3 accounts for more than 0% but less than 2%; and/or K2O accounts for 0.8 to 3%; and/or CaO accounts for 0 to 3%; and/or BaO accounts for 0 to 3%; and/or SnO2 accounts for 0.05 to 0.4%; and/or SrO accounts for 0 to 1%; and/or La2O3 accounts for more than 0 but less than or equal to 8%; and/or Y2O3 accounts for more than 0 but less than or equal to 8%; and/or Nb2O5 accounts for 0 to 5%; and/or Ta2O5 accounts for 0 to 5%; and/or WO3 accounts for 0 to 1%; and/or the clarificant accounts for 0 to 2%.

7. The glass ceramic according to claim 1, wherein SiO2/Li2O ratio is 4.5 to 9.5; and/or ZrO2/Li2O ratio is more than 0 but less than 0.35; and/or Al2O3/(Na2O+Li2O) ratio is 0.7 to 1.8; and/or Li2O/Na2O ratio is 1.5 to 7.5.

8. The glass ceramic according to claim 1, wherein Na2O accounts for 4 to 8%, preferably more than 5% but less than or equal to 8%; and/or Al2O3 accounts for 7 to 15%; and/or ZrO2 accounts for 1 to 2%; and/or P2O5 accounts for 1 to 2%; and/or K2O accounts for 1 to 3%; and/or CaO accounts for 0 to 1%; and/or BaO accounts for 0 to 1%; and/or SnO2 accounts for 0.05 to 0.2%; and/or the clarificant accounts for 0 to 1%; and/or SiO2/Li2O ratio is 5 to 9; and/or ZrO2/Li2O ratio is more than 0 but less than or equal to 0.30; and/or Al2O3/(Na2O+Li2O) ratio is 1 to 1.5; and/or Li2O/Na2O ratio is 2 to 7, preferably Li2O/Na2O ratio is 2 to 6.

9. The glass ceramic according to claim 1, wherein TiO2 accounts for 0.5 to 5%, preferably TiO2 accounts for 1.5 to 4%; and/or ZrO2+P2O5+TiO2 account for 0.5 to 10%, preferably ZrO2+P2O5+TiO2 account for 1 to 8%, and more preferably ZrO2+P2O5+TiO2 account for 2 to 6%.

10. The glass ceramic according to claim 1, wherein TiO2 accounts for 2 to 9.5%, preferably TiO2 accounts for 5 to 8.5%; and/or ZrO2+P2O5+TiO2 account for 1 to 16%, preferably ZrO2+P2O5+TiO2 account for 2 to 12%.

11. The glass ceramic according to claim 1, further containing NiO and/or Ni2O3 with total amount thereof not more than 6%, preferably not more than 4%, more preferably not more than 3%, and a lower limit of the total amount thereof more than 0.1%; or containing Pr2O5 with content not more than 8%, preferably not more than 6%, more preferably not more than 5%, and a lower limit of the content thereof more than 0.4%; or containing CoO and/or Co2O3 with total amount thereof not more than 2%, preferably not more than 1.8%, and a lower limit of the total amount thereof more than 0.05%; or contains Cu2O and/or CeO2 with total amount thereof not more than 4%, preferably not more than 3%, and a lower limit of the total amount thereof more than 0.5%; or containing Fe2O3 with content not more than 8%, preferably not more than 5%, and more preferably not more than 3%; or containing Fe2O3 and CoO with CoO not more than 0.3%; or containing Fe2O3 and CO2O3 with CO2O3 not more than 0.3%; or containing Fe2O3, CoO and NiO; or containing Fe2O3, CO2O3 and NiO; or containing Fe2O3, CoO and CO2O3 with a lower limit of the total amount of CoO and CO2O3 more than 0.2%; or containing Fe2O3, CoO, NiO and Co2O3; or containing MnO2 with content not more than 4%, preferably not more than 3%, and lower limit of the content more than 0.1%; or containing Er2O3 with content not more than 8%, preferably not more than 6%, and a lower limit of the content thereof more than 0.4%; or containing Nd2O3 with content not more than 8%, preferably not more than 6%, and a lower limit of the content thereof more than 0.4%; or containing Er2O3, Nd2O3 and MnO2 with Er2O3 content within 6%, Nd2O3 content within 4%, and MnO2 content within 2%, and a lower limit of the total amount thereof more than 0.9%; or containing Cr2O3 with content not more than 4%, preferably not more than 3%, more preferably not more than 2%, and a lower limit of the content thereof more than 0.2%; or containing V2O5 with content not more than 4%, preferably not more than 3%, more preferably not more than 2%, and a lower limit of the content thereof more than 0.2%.

12. The glass ceramic according to claim 1, wherein a Li2Si2O5 crystalline phase accounts for 20 to 40% of the glass ceramic by wt %, preferably 20 to 35%, more preferably 20 to 30%, and further preferably 20 to 25%.

13. The glass ceramic according to claim 1, wherein a quartz and a quartz solid solution crystalline phase account for 15 to 30% of the glass ceramic by wt %, preferably 20% to 30%, and more preferably 25 to 30%.

14. The glass ceramic according to claim 1, wherein the Li2Si2O5 crystalline phase and the quartz and the quartz solid solution crystalline phase are main crystalline phases, the total content thereof is lower than 50% of the glass ceramic by wt %, preferably below 48%, and more preferably below 46%.

15. The glass ceramic according to claim 1, wherein a LiAlSi4O10 crystalline phase accounts for not more than 15% of the glass ceramic by wt %.

16. The glass ceramic according to claim 1, wherein an upper limit of the glass liquidus temperature is 1,450° C., preferably 1,400° C., more preferably 1,380° C., and most preferably 1,320° C.

17. The glass ceramic according to claim 1, wherein a thermal conductivity of the glass is above 2 W/m·k at room temperature (25° C.).

18. A glass ceramic substrate made of the glass ceramic according to claim 1 by chemical tempering.

19. The glass ceramic substrate according to claim 18, wherein a Vickers hardness (Hv) is above 600 kgf/mm2, preferably above 650 kgf/mm2, and more preferably above 700 kgf/mm2.

20. The glass ceramic substrate according to claim 18, wherein the glass ceramic substrate does not break when a 32 g steel ball falls down from a height of 500 mm, preferably from a height above 650 mm, and more preferably from a height above 800 mm.

21. The glass ceramic substrate according to claim 18, wherein a three-point bending strength is above 450 Mpa, preferably above 600 Mpa, and more preferably above 800 Mpa.

22. The glass ceramic substrate according to claim 18, wherein a compressive stress layer is formed by ion exchange, and a compressive stress value thereof is above 300 Mpa, preferably above 400 Mpa, and more preferably above 500 Mpa.

23. The glass ceramic substrate according to claim 18, wherein the compressive stress layer has a thickness above 1 m, preferably above 5 m, more preferably above 8 m.

24. A portable electronic device, containing the glass ceramic according to claim 1.

25. A portable electronic device, containing the glass ceramic substrate according to claim 18.